Hi all,
While not disagreeing with any of the technical points Jim makes, I simply
want to mention that I had a twinlead-fed 80-meter dipole at my old New Jersey
QTH. It was supported at each end by a tree approximately 60 feet high. The
feedline came down perpendicular to the dipole into a Heathkit SA-2060A tuner
at the point where it entered the shack. I used it on all HF bands, mostly 80
through 20 meters.
As Jim pointed out, there is no way to totally eliminate unbalanced currents
from such a set-up, but the geometry at least kept their level down.
This was obviously not a contest antenna, if for no other reason than the
time it took to change bands. Its performance was good enough, however, to keep
me on the Honor Roll with all except BS7, which I later worked from Arizona. I
never ran a full gallon into it, just an SB-200. On 20 and 15, it easily
outperformed a 2-el triband beam at 30 feet, which I eventually took down. As
the old saying says, "height beats gain." I didn't notice noise as a big
problem, but the neighborhood was relatively quiet.
Compared with a coax-fed fan dipole, its greatest advantage was mechanical:
its very light weight, which enabled it to last almost indefinitely. With no
center support, a big-coax-fed antenna would have drooped considerably unless
it were kept so tight as not to withstand the frequent high winds.
Just one ham's experience.
73 Ray W2RS
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